Textural Enhancement and Glycemic Potency Reduction of Sugarcane Fiber-Incorporated White Bread with Ascorbic Acid and Xanthan Gum

The prevalence of Type 2 diabetes is increasing globally, with an estimated 425 million adults diagnosed in 2017 and is projected to reach 693 million by 2045. Among Southeast Asian countries, Singapore has been reported to have the highest prevalence of Type 2 diabetes with 11.6% adults diagnosed in 2021. White bread, known for its elevated glycemic index, causes a rapid spike in blood glucose levels post-consumption. Incorporating dietary fibers, such as sugarcane fiber (SCF), into bread mitigates this risk. However, challenges faced includes loss of product quality, decreased loaf volume, inferior sensory characteristics, and increased loaf hardness. This study aimed to address these challenges by incorporating dough improvers into SCF-incorporated breads.

This study investigated the impact of incorporating xanthan gum (0.75 or 1.5%) and ascorbic acid (0.02%), individually and synergistically, into SCF-incorporated breads (5% or 10%). The subsequent evaluation focused on discerning the effects of these additions on the bread's texture, sensory attributes, and glycemic potency. Adding xanthan gum and a combination of ascorbic acid and xanthan gum into 5% SCF-incorporated breads significantly reduced bread hardness (from 18.08 to 13.53–18.58 N) and increased specific volume from (from 5.77 to 5.70–6.04 cm³/g). SEM images revealed larger, uneven holes in xanthan gum-incorporated breadcrumbs due to its high elasticity. FTIR spectrum results showed that the combination of SCF, xanthan gum, and ascorbic acid led to a more flexible gluten structure, marked by increased β-turn (from 13.3% to 19.0–26.6%) and decreased α-helix protein structures (from 50.5% to 39.3–44.7%). In in-vitro digestibility studies, all SCF-incorporated breads exhibited lower glycemic index than the reference (GI=70). SCF-incorporated breads with 1.5% xanthan gum and 0.02% ascorbic acid reported the lowest GI values (≤ 55). Results obtained from this study can be applied in commercialization of bakery products and potential management of blood-sugar diseases.